German Chancellor Angela Merkel and her Social Democratic rival Martin Schulz rallied voters on the eve of the September 24 general election, urging them to reject the first right-wing party expected to enter parliament in force since the end of World War II.

Merkel, the clear frontrunner after 12 years in power, is seeking a fourth term in office, and her conservative bloc of the Christian Democratic Party and Bavarian-only Christian Social Union has a strong lead in the polls.

Although support has been eroding slightly over the past week, surveys show Merkel's bloc leading with between 34 to 37 percent support, followed by the Social Democrats with 21 to 22 percent.

Before heading for cities in northern Germany, Merkel told supporters in Berlin on September 23 that they needed to keep up their efforts to sway undecided voters, saying "many make their decision in the final hours."

Merkel's main challenger, Social Democrat Martin Schulz, attended a rally in western Germany in the city of Aachen.

Both Merkel and Schulz called on the electorate to resist the right-wing populist Alternative for Germany (AfD), which has vituperated against the influx of around 1 million mostly Muslim migrants and refugees.

Foreign Minister Sigmar Gabriel, also a Social Democrat, warned that "for the first time since the end of the second World War, real Nazis will sit in the German parliament."

The AfD, which has links to the far-right French National Front and Britain's ultranationalist UKIP, appears assured of gaining seats in the national parliament for the first time, with 10 to 13 percent support in the polls.

The International Auschwitz Committee warned that the "conglomerate of anti-Semites, enemies of democracy and nationalistic agitators" will bring "an inhuman coldness" to the German parliament.

In addition to the AfD, the Greens, the Free Democratic Party, and the Left Party were all poised to enter parliament with poll numbers between 8 and 11 percent.